Force users to use specified DNS server
From MikroTik Wiki
This is just simple firewall rule which will force all Your users behind RB to use DNS server which You will define.
In /ip firewall nat
add chain=dstnat action=dst-nat to-addresses=192.168.88.1 to-ports=53 protocol=tcp dst-port=53
add chain=dstnat action=dst-nat to-addresses=192.168.88.1 to-ports=53 protocol=udp dst-port=53
This rule will force all users with custom defined DNS server to use 192.168.88.1 as their DNS server, this rule will simply redirect all request sent to ANY-IP:53 to 192.168.88.1:53
--Marko 12:29, 6 July 2010 (UTC)